Energy Policy 60 (2013) 481–486

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Energy Policy

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journal homepage: www.elsevier.com/locate/enpol

The status of energy conservation in Taiwan's cement industry

Te-Li Su a, David Yih-Liang Chan b, Ching-Yuan Hung c, Gui-Bing Hong a,n

a Department of Cosmetic Application and Management, St. Mary's Medicine, Nursing and Management College, 100, Lane. 265, Section 2, Sanxing Road,Sanxing Township, Yilan County, Taiwanb Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Room, 272, Building. 22-1, 195, Sec. 4, Chung Hsing Road,Chutung, Hsinchu, Taiwanc Service Systems Technology Center, Industrial Technology Research Institute, Rm. 225, Bldg. 52, 195, Section 4, Chung Hsing Road, Chutung, Hsinchu, Taiwan

H I G H L I G H T S

� This study summarizes the energy savings implemented in Taiwan's cement industry from the on-line Energy Declaration System.

� The energy audit group audited seven Taiwanese cement plants in 2011 and revealed energy saving potential was 1708.5 KLOE.� This work aims to examine what Taiwan has done and also describes the current status in cement industry.� In addition, some potential energy conservation opportunities or measures are revealed in this paper.

a r t i c l e i n f o

Article history:Received 23 November 2012Accepted 2 April 2013Available online 17 May 2013

Keywords:Energy auditCement industryTaiwan

15/$ - see front matter & 2013 Elsevier Ltd. Ax.doi.org/10.1016/j.enpol.2013.04.002

esponding author. Tel.: +886 3 9897396; fax:ail address: lukehong@smc.edu.tw (G.-B. Hon

a b s t r a c t

The cement industry represents one of the most energy intensive sectors in Taiwan. Energy audits are thedirect tools which are employed to help reduce energy consumption. The objectives of energy audits areto establish energy audit systems, provide on-site energy audit service and reduce production cost.This study summarized the energy savings implemented in Taiwan's cement industry; the data wereobtained from the on-line Energy Declaration System in 2010. The total implemented energy savingsamounted to 68,512 kilo liter of crude oil equivalent (KLOE). The energy audit group audited sevenTaiwanese cement plants in 2011 and revealed an energy saving potential of 2571.6 MWh of electricityand 1002.8 KLOE of thermal energy. The total potential energy saving was 1708.5 KL of crude oilequivalent (KLOE), equivalent to a 4560 t reduction in CO2 emissions, representing the annual CO2

absorption capacity of a 122 ha forest plantation.& 2013 Elsevier Ltd. All rights reserved.

1. Introduction

The total annual cement production in Taiwan, by 18 kilnsof 12 plants, was approximately 20 million tons in 2010–2011. Ingeneral, there are three principal steps in cement production: rawmaterial processing, clinker burning processing and finish grind-ing processing. The raw material and clinker burning processingcan be classified as wet process and the dry processing, respec-tively. The clinker is produced from the raw material process insequence operations: preheating the raw materials; precalcina-tion, burning inside the kiln and clinker cooling (UNIDO, 1994;Sattari and Avami, 2007). Producing clinker is the most energy-intensive step, and the dry process is more energy-efficient.Cement production processes are costly operations as well ashighly intensive in terms of energy (Kabir et al., 2010). Energy

ll rights reserved.

+886 3 9899114.g).

accounts for 40–60% of the total production cost (Dumas, 1990;Worell et al., 2000). The cement industry is one of the largest usersof fossil energy in Taiwan's manufacturing sector. The concentra-tion of greenhouse gases (GHG) from manufacturing factoryactivities and vehicle emissions has increased significantly overthe years. Energy intensity (from the environmental aspect) andthe economic perspective are closely intertwined; this integralrelationship must be thoroughly considered in order to increaseefficiency and decrease costs (Avami and Sattari, 2007). Conse-quently, energy research institutes and governmental energydepartments from various nations are all committed to developingmethods for accurately assessing energy efficiency; the results canbe used as references for policy-making. Additionally, the energyutilization status can be compared among different countries toachieve the common aim of reducing greenhouse gas emissions.Numerous analytical studies have been undertaken on energyconservation in regard to different industries. Energy use, savingsand energy efficiency of machines used in industrial sectors havebeen studied by many researchers. Plant operational energy audits

T.-L. Su et al. / Energy Policy 60 (2013) 481–486482

and optimization evaluations are regularly carried out to reducespecific energy consumption and optimize output (Lowes andBezant, 1990). Increasing energy efficiency is the most directmethod for reducing GHG emissions. Little or no investment isneeded to achieve a 10–30% reduction in GHG emissions (Ghaddarand Mezher, 1999). Energy auditing has been demonstrated to bean effective energy management program (Engin and Ari, 2004;Lafarge Canada Inc., 2002) and it has been applied to calculate andevaluate the possibility of reducing the energy demand of eachoperational unit in the manufacturing process. Demand can bereduced through low cost energy conservation measures (Enginand Ari, 2004).

Taiwanese industry is primarily small and medium scale, andenergy management technology lately has been increasinglyadopted. To alleviate the adverse environmental impact (e.g., globalclimate change, global warming and atmospheric emission pollu-tants), the United Nations passed the Framework Convention onClimate Change (FCCC) in 1992 to limit greenhouse gas emissions.Recently, the government has also actively promoted the concept ofsaving energy and implemented energy saving measures. Accordingto the “Energy Management Law”1 of Taiwan, energy users shouldobserve the regulations promulgated by the central authority; theseinclude conducting an energy audit, as well as setting an energyconservation target and action plan. However, industry usuallyfocuses on production and still has a strong need for assistance inregard to adopting and carrying out energy saving measures.Increased energy utilization efficiency is necessary for industryto obtain the desired results of energy audits. This work aimsto examine what Taiwan has done in terms of its energy conserva-tion policy, and also describes the current status in the cementindustry. In addition, some potential energy conservation opportu-nities or measures are presented in this paper.

2. Current status in the cement industry

According to the statistical information of the Mineral CommoditySummaries 2012 (U.S. Geological Survey, Mineral CommoditySummaries, 2012), total global cement production was estimated at3400 million tons in 2011. China was the largest producer, accountingfor 58.8% of the global cement production, followed by India (6.2%),the USA (2.0%), Turkey (1.9%) and Brazil (1.8%), as shown in Table 1.Energy consumption in the cement industry will continue to increasein conjunction with market growth. Taiwan's industries are primarilysmall and medium scale and the country has extremely limited coaland petroleum resources. Taiwan depends on imports for approxi-mately 99.3% of its primary energy; rapid economic development hasrapidly increased the demand for energy and, in particular, electricity.The cement industry represents one of the most energy intensivesectors in Taiwan. In 2010, Taiwan's cement industry consumed1.8 million KLOE for its total annual production. Meanwhile, theentire industrial sector consumed 64.7 million KLOE, signifying anincrease of 9.0% a yearly. In comparison with 2009, energy use in2010 increased by 2.1% (predominantly in electricity and coal), asshown in Table 2. The average energy use in the industrial sectorincreased by 2.9%, while average cement industry energy usedecreased by 4.8% during the 2006–2010 periods. After the negativeinfluence of the global financial crisis in 2008, the production ofcement decreased and induced the energy consumption to decreasesignificantly.

Energy intensity (E/GOV) is a measure of the energy efficiencyof a nation's economy. E/GOV in this study is calculated as units

1 Energy Management Law is promulgated by Taiwan's President in August 8,1980 (modified in July 8, 2009) to serve the purpose of upgrading energymanagement aimed at rational and efficient utilization of energy.

of energy (E) per unit of gross output value (GOV) in the cementindustry. Fig. 1 shows the energy intensity of the cement industryin recent years. It can be seen that the energy intensity ofTaiwanese cement industry was 1.79� E−2 (E/GOV) LOE per NTdollar2 in 2010, having decreased by 2.4% compared to 2009. Thereason for the improved energy efficiency from 2006 to 2010 wasthe positive influence of Taiwan's energy conservation policy.Due to the fluctuating cement price from year to year, usingenergy intensity to gauge energy conservation efficacy might bemisleading. Therefore, the annual production of cement and unitproduction energy consumption was also listed in Table 2. Thegovernment of Taiwan has taken substantial preparatory measuresand established an energy audit group to help energy usersenhance energy efficiency, reduce CO2 emissions, and promoteenergy savings by all industrial sectors. During 2006–2010, cementproduction has decreased and energy consumption thus has alsodecreased. Fig. 2 shows the recent energy intensity for the cement.Evidently, the energy improvement potential of cement is over 10%at least compared with the cement industry of China.

3. Energy auditing methodology

Energy audits are the most comprehensive approach to improvean existing system's energy efficiency (Avami and Sattari, 2007).There are three objectives of energy audits in Taiwan: (1) assistingenergy users to establish energy audit systems; (2) assisting energyusers to implement energy management and set energy saving goals;and (3) providing on-site energy audits and guidance, technologyand information services related to energy saving. The energy auditprocess involves the following stages:

(a)

2

curr

Before conducting an on-site audit, the energy audit groupstudies the historical consumption trends and technologicalinformation of the plant.

(b)

During this on-site audit, the auditors discuss the main energyconsuming equipment with representatives of the energy useror equipment operators.

(c)

The auditors compare the operating manual and equipmentspecifications of the energy consuming equipment to theoperation and maintenance records provided by the energyuser and check for abnormalities.

(d)

All relevant major energy consuming equipment or manufac-turing processes' data used for the analysis are obtained eitherfrom the plant control panel or by on-site measurement usingthe relevant instruments (such as IR thermal analyzer, ultra-sonic flow meter, illumination meter, and so on).

(e)

After the on-site audit, any potential for saving opportunitiesis identified and the economic calculations are done toproduce an on-site energy audit report.

(f)

Finally, a database is established which contains possible savingopportunities, the economic calculations and energy consump-tion data for use by the government in developing its energypolicy, as well as for use by other energy users as a reference.

4. Energy conservation technology and potential for thecement industry

According to the report issued by the Bureau of Energy,Ministry of Economic Affairs, Taiwan, the energy cost representsover 35% of total production costs in the production of cement.

The NT dollar (New Taiwan dollar), or simply Taiwan dollar, is the officialency of the Taiwan Area of the Republic of China (ROC) since 1949.

1.98E-021.95E-02

1.85E-02 1.83E-02

1.79E-02

1.70E-02

1.90E-02

2.10E-02

E/G

OV

(LO

E/$

)

T.-L. Su et al. / Energy Policy 60 (2013) 481–486 483

The cement industry thus is a very energy-intensive industry. Rawmaterial mill, rotary kiln and cement mill account for most of theindustry's energy consumption, together accounting for over 90%of total cement industry energy consumption (Chan et al., 2007).Generally, energy consumption in the cement industry is providedby electricity, coal and petroleum products. Over 90% of the fuelsused, such as coal, are consumed in clinker production. Around39.0% electricity is used for finish grinding and about 28% each isused for raw material processing and clinker burning, as shown inFig. 3. The energy conservation technology and potential areas forthe cement industry can be categorized to the support andproduction process (Trygg and Karlsson, 2005). The productionprocesses produce products, while the support processes supportproduction.

4.1. Production process

There are three principal steps in cement production: rawmaterial processing, clinker burning and finish grinding. The rawmaterial processing and clinker burning can be classified as wetand dry processes, respectively. All of the cement produced inTaiwan uses the dry process. The energy conservation opportu-nities are as follows:

Table 1World production of cementa (unit: million tones).

Country 2010 2011b Percentage of 2011

United States (includes Puerto Rico) 67.2 68.4 2.0Brazil 59.1 62.6 1.8China 1880.0 2000.0 58.8Egypt 48.0 45.0 1.3Germany 29.9 33.0 1.0India 210.0 210.0 6.2Indonesia 22.0 22.0 0.6Iran 50.0 52.0 1.5Italy 36.3 35.0 1.0Japan 51.5 47.0 1.4Republic of Korea 47.2 46.0 1.4Mexico 34.5 35.0 1.0Pakistan 30.0 30.0 0.9Russia 50.4 52.0 1.5Saudi Arabia 42.3 44.0 1.3Spain 23.5 20.7 0.6Thailand 36.5 36.0 1.1Turkey 62.7 64.0 1.9Vietnam 50.0 50.0 1.5Other countries 480.0 480.0 14.1

World total 3310.0 3400.0 100.0

a Source: Mineral Commodity Summaries (2012).b Estimated.

Table 2Energy use summary of Taiwan's cement industry.a

Year Annual production of cement(million tones)

Energy type (KLOE)b

Electricity Coal and coalproducts

Petroleumproducts

Summ

2006 13.9 612,884 1,686,149 103,374 2,4022007 12.9 565,694 1,559,068 105,732 2,230,2008 10.7 520,942 1,454,614 106,283 2,0812009 9.9 478,673 1,212,236 100,489 1,7912010 10.1 483,467 1,238,772 106,166 1,828

a Source: AREMOS Data Bank.b Heat value transfer: 1 kWh¼2236 kcal; 1liter fuel oil¼9200 kcal; 1 kg steam coalc Unit transfer: 1 kcal¼4.184 kJ.

(a)

atio

,407494,843,398,405

¼64

Fig.RITE

Raw material process(i) Transport system: powder materials, such as feed, are

usually transported by pneumatic or mechanical con-veyors. Since the energy consumption of mechanicalconveyors is less than that required for the pneumatictype, the use of the mechanical type is preferred. Basedon Holderbank (1993), the average energy savings are

n Indsec

56,62,61,59,64,

00 kca

1.50

F

2. En2008

ustrialtor (KLOE)

National energyconsumption (KLOE)

Unit production energyconsumption (GJ/tones)c

613,898 104,225,438 4.52480,733 110,156,465 4.59279,892 107,550,197 4.56397,639 104,972,381 4.29735,852 111,926,248 4.23

l and 1 m3 NG¼9000 kcal.

E-022006 2007 2008 2009 2010

Year

ig. 1. Energy intensity (E/GOV) of cement industry, 2006–2010.

ergy intensity (GJ/ton) of cement industry, 2006–2010 (Ke et al., 2012;).

Rawmaterialprocess28.0%

Clinkerburning28.4%

Finishgrinding39.0%

Others4.6%

Fig. 3. Electricity consumption ratio by process in the cement industry.

T.-L. Su et al. / Energy Policy 60 (2013) 481–486484

estimated at 2.0 kWh/ton raw material with a switch tomechanical type conveyor system.

(ii) Blending system: if raw materials are completely mixed sothat they are homogenized, the mixture will burn moreefficiently in the kiln. In general, the energy consumptionof gravity-type homogenizing silos is significantly lessthan that of the air-fluidized type. If old equipmentis replaced with the gravity-type silos, the energy con-servation is estimated at 0.9–2.3 kWh/ton raw material(Holderbank 1993; Alsop and Post, 1995).

(iii) The use of advanced mills, such as high-efficiency rollermills, high pressure pressing mills, or horizontal rollermills to replace traditional ball mills for raw materials orcoal grinding will save electricity. If a vertical or horizon-tal roller mill is installed, the energy savings are estimatedat 6–7 kWh/ton raw materials (Cembureau, 1997).

(iv) Classifier/separator: if raw materials remain in the separatorlonger in the high efficiency classifier, over grinding will beavoided and electricity consumption will be reduced 8% ofthe specific electricity use (Holderbank 1993); therefore, highefficiency classifiers are used in modern plants.

(b)

Clinker burning process(i) Kiln combustion system: if the shape of the flame, air/fuel

ratio and air usage are optimized, the kiln combustionsystem will be improved and energy consumption willbe reduced 2–10%.

(ii) If seals and insulating refractory are used for the kiln,fuel consumption in the kiln will be reduced 0.4% by theinsulation materials.

(iii) Energy reduction will result from the partial substitutionof fossil fuels with biomass and waste fuels (such aswaste tire, waste tire-derived fuel) in the kiln.

(iv) Clinker cooler system: three types in common use are:planetary (or satellite), traveling and reciprocating gratecoolers. If the cooler operation is improved or the satellitecooler is replaced by a grate type, heat recovery efficiencywill increase and fuel consumption will decrease. Theenergy saving is estimated at 0.14 MBtu/ton clinker forretrofitting a grate cooler (Holderbank 1993).

(v) If newer cyclones, which are the basic element inpreheating systems, are installed with lower pressurelosses, the electricity consumption of the SP (suspensionpreheaters) kiln exhaust gas fan system could be reduced0.6–1.0 kWh/ton clinker.

(vi) The Taiwanese cement industry mostly employs SP andNSP (new suspension preheaters) kilns. Since the energyefficiency of an NSP kiln is superior to all conventionalkilns, the use of NSP kilns is recommended.

(vii) Waste heat recovery from cooler exhaust gas could beapplied to raw material drying, the kiln preheater andpower generation.

(viii) If a multi-stage preheater and precalciner are added, theproduction of the plant will increase 50% and energyconsumption will be reduced 25%.

(c)

Finish grinding process(i) Because the energy efficiency of traditional ball mills is

lower than that of advanced mills such as roller presses,roller mills, etc, the use of advanced mills is preferred.If advanced mills are installed, the energy savings areestimated at 20–30 kWh/ton clinker (Cembureau, 1997).

(ii) The addition of pre-grinding combined with a ball mill willreduce electricity consumption 6–22 kWh/ton cement(Cembureau, 1997).

(iii) If high efficiency classifiers or separators are used in thefinish grinding process, the product quality will improved,the production will increase 25% and electricity consump-tion will reduce of 6 kWh/ton cement (Parkes, 1990).

(iv) Management of optimum grinding media, such as increasingball charge distribution and surface hardness, is a potentialtool for reducing energy consumption.

4.2. Support process

(a)

Lighting systemElectricity consumption of the lighting system accounts forless than 1.5% of the total electricity use in the cementindustry. The suggested energy conservation measures wouldinclude the following.(i) The factory building adopts roof skylights: if daylight is used

as an alternative light source, lighting energy consump-tion would be reduced (Kim and Kim, 2007).

(ii) Traditional fluorescent lighting should be replaced with HF(high frequency) fluorescent lighting to save energy for 50%.

(iii) If mercury lighting is changed to high-pressure sodium orcomposite metal lamp, lighting energy would be saved 50%.

(iv) Lighting control: if an automatic control system is installed,lights could be turned off during non-working hours; manualcontrol, such as turning off lights when leaving, could alsosave electricity.

(b)

Electrical system(i) The utilization rate can be increased at off peak times.

Moreover, reasonable reductions in contract capacity canbe made.

(ii) A lower power factor will result in higher electricityconsumption. The power factor can be corrected by mini-mizing the idling of electric motors and installing capaci-tors to reduce electricity consumption.

(c)

Air blower, pump and motor(i) Proper motor size determination: if oversized motors are

replaced with properly sized motors, electricity consump-tion will be reduced.

(ii) These systems can adopt inverter control, with regularreplacement carried out.

(iii) Electricity use would be saved vary between 7 and 60% ifthe motor is switched to an energy-efficient motor-drivensystem such as ASDs (adjustable speed drives).

(d)

Air compressor systemElectricity consumption of the air compressor system is rela-tively small in the cement industry; however, compressed air

Table 3Total energy saving implemented for Taiwan's cement industry in 2010.

Energy savingitems

Energy saving implemented Investment costs(million NT dollars)

Economic benefit b

(million NT dollars/Year)Electricity (MWh) Steam coal (Ton)a Fuel oil (kiloliters) Natural Gas (cubic meter)

Process control system 184,566 20,878 1655 292,932 61,323 299.9 408.0Air conditioning system 4381 – – – 1065 13.6 9.0Air compressor system 6516 – – – 1584 3.6 11.7Lighting system 2234 – – – 543 2.6 4.6Motor system 2307 – – – 561 2.4 5.1Electrical system 1321 – – – 321 0.5 2.4Boiler system 930 – 175 – 401 5.2 2.2Others – 2938 245 435,116 2714 4.9 15.3

Summary 202,255 23,816 2075 728,048 68,512 332.7 458.3

a Heat value transfer: 1 kWh¼2236 kcal; 1liter fuel oil¼9200 kcal; 1 kg steam coal¼6400 kcal; 1 m3 NG¼9000 kcal.b Economic benefit is defined as that saved due to a reduction in energy use.

Table 4CO2 reduction by cement plants in 2010.

Energy saving items Carbon dioxide reduction (Ton-CO2)a

Process control system 181,305Air conditioning system 2960Air compressor system 4403Lighting system 1509Motor system 1559Electrical system 893Boiler system 1129Others 8805

Summation (Ton-CO2) 202,563

a Carbon dioxide emission coefficients: (1) electricity: 2.78 t-CO2/KLOE;(2) steam coal: 3.53 t-CO2/KLOE; (3) fuel oil: 2.86 t-CO2/KLOE and (4) natural gas:2.09 t-CO2/KLOE.

Table 5Total energy saving potential for Taiwan's cement industry in 2011.

Firms Energy saving potential Carbon dioxidereduction potential(Ton-CO2)a

Electricity Thermal Total energy

3

thedeclaof th

T.-L. Su et al. / Energy Policy 60 (2013) 481–486 485

may be the most expensive form of derived energy in a plant.In general, the compressor has to work more than it ought to inorder to maintain pressure in the compressed air line, whichleads to a higher electricity consumption than is necessary. Theenergy conservation opportunities would include the following:(i) System controls are one of the most important elements

of an air compressed system, and also a central factor inair compressor efficiency. If an air compressor system'spressure is set too high, output pressure and air suckingtemperature are reduced.

(ii) If the pipe lengths and diameter size, as well as thepositioning of the control loop are suitable, the com-pressed air pressure downstream to the receiver willreduce energy consumption.

(iii) A well-known problem with air compressor systems isleakage. During the air compressor operation process,over 30% of the energy consumed is due to surgeand leakage; therefore, leakage reduction will decreasethe energy loss of an air compressor system to lessthan 30%.

(iv) A lower inlet air temperature will result in lower energyconsumption of the compressor. According to a ruleof thumb, each 3 1C will reduce 1% energy use of thecompressor.

TheITRI (re the gov

(MWh) energy(KLOE)

saving (KLOE)

A 33.7 – 8.4 21B 723.6 – 179.8 451C 156.1 – 38.8 97D 328.9 – 81.7 205E 1175 962 1318.1 3570F 30.3 40.8 51 139G 124 – 30.8 77

Summary 2571.6 1002.8 1708.5 4560

a Unit conversion: (1) 1 kWh¼2236 kcal; (2) 1 LOE¼9000 kcal; (3) electricity:2.78 t-CO2/KLOE; (4) steam coal: 3.53 t-CO2/KLOE; (5) fuel oil: 2.86 t-CO2/KLOE and(6) natural gas: 2.09 t-CO2/KLOE.

5. Results and discussion

5.1. Energy saving implementation

Energy users in Taiwan should observe the “Energy ManagementLaw” by conducting an energy audit, as well as setting up an energyconservation target and an action plan. The energy use status andenergy saving implemented every year should be declared via theon-line Energy Declaration System3 (Hong et al., 2010). The energysaving implemented in 2010 of cement producers was 202,255MWhof electricity, 23,816 t of steam coal, 2075 kiloliters of fuel oil, and72,8048m3 of natural gas (NG). The total energy saving implementedwas 68,512 KLOE, as listed in Table 3. Based on the CO2 emissioncoefficients reported by Chan et al. (2010), it is estimated that the totalCO2 reduction was 202,563 t, as listed in Table 4. The investment costsand economic benefit are also listed. From the perspective of CO2

on-line Energy Declaration System is a website which is established byIndustrial Technology Research Institute of Taiwan). Energy users cane energy use status and energy saving potential per year for the referenceernment.

reduction, the greatest CO2 reduction lies in process control, whichpotentially comprises 89.5% of total CO2 reduction.

5.2. Energy saving potential

Energy audits are the immediate method to improve energyefficiency, reduce energy consumption and decrease atmospheric

T.-L. Su et al. / Energy Policy 60 (2013) 481–486486

emissions. Seven Taiwanese cement producers were audited in 2011;the energy saving potential identified was 2571.6 MWh of electricityand 1002.8 KLOE of thermal energy. The total energy saving potentialthus was 1708.5 KLOE, as listed in Table 5. Based on the CO2 emissioncoefficients reported by Chan et al. (2010), it is estimated that energyusers can reduce CO2 emissions by 4560 t, as listed in Table 5.According to the study of Lasco et al. (2002), plants have thefollowing CO2 absorbing capability: tree plantations (10.09 tC/ha/yr)4 4coconut (4.78 tC/ha/yr)4brush land (4.29 tC/ha/yr)4naturalforest (0.92 tC/ha/yr). The energy saving potential derived from thison-site audit thus is equivalent to the annual CO2 absorption capacityof 122 ha of plantation forest or 1340 ha of natural forest.

6. Conclusions

Energy audits are a pragmatic approach to evaluate the designand performance of energy systems. Substantial preparatory mea-sures have been undertaken; an energy audit group and on-lineEnergy Declaration Systemwere established by the Bureau of Energyof the Ministry of Economic Affairs5 to help energy users improveenergy efficiency, CO2 emissions and energy conservation by allindustrial sectors. The energy saving implemented from the on-lineEnergy Declaration System in 2010 of cement producers was around68,512 kt of oil equivalent, equivalent to a 202,563 kt of potentialreduction in CO2 emissions. In addition, energy-saving opportunitiesand potential were identified and evaluated. The energy audit groupaudited seven Taiwanese cement plants in 2011 and provided recom-mendations and technical services. On-site energy audits revealedthe energy saving potential of 2571.6 MWh of electricity and1002.8 KLOE of thermal energy. The total potential energy savingwas 1708.5 KL of crude oil equivalent (KLOE), equivalent to a 4560 treduction in CO2 emissions, representing the annual CO2 absorptioncapacity of a 122 ha forest plantation. According to the experience ofenergy audit implemented, we recommended that: (a) the energyaudit should be implemented and supported; (b) the governmentand enterprises should cooperate closely to improve the energyefficiency and GHG emission intensity; (c) the government shouldseek to achieve improvements in energy intensity, carbon dioxideemission intensity, industrial structure; (d) new energy conser-vation technologies should be developed and encouraged for furtherreductions energy consumption and GHG emission and (e) thefinancing mechanisms should be developed to encourage enterprises'adoption for further reductions in GHG emission.

Acknowledgment

The authors would like to thank the Bureau of Energy, Ministryof Economic Affairs, Taiwan, for financially supporting thisresearch. The anonymous reviewers are also appreciated for theircomments.

4 The unit of tC/ha/yr indicates ton carbon.5 Since energy plays a vital role in national economic development, the

government established the Energy Commission under the Ministry of EconomicAffairs in November 1979, and reorganized it as the Bureau of Energy in July 2004.

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